Ukraine claimed to have sunk a Russian military supplies ship on Snake Island, a small but crucial outpost in the Black Sea. At the same time, relatives of Ukrainian soldiers besieged in Mariupol's steelworks called for their rescue.
According to some defense sources, the renewed conflict around Snake Island in recent days may become a battle for control of the western Black Sea coast as Russian forces struggle to advance in Ukraine's north and east.
"Thanks to the actions of our naval seamen, the support vessel Vsevolod Bobrov caught fire - it is one of the newest in the Russian fleet," said Serhiy Bratchuk, a spokeswoman for the Odesa regional military administration.
Reuters was incapable of independently confirming the details. The Russian Ministry of Defense did not reply quickly to a request for comment.
Maxar, a private U.S. corporation, published satellite imagery depicting the aftermath of suspected missile attacks on a Russian Serna-class landing craft near the island, close to Ukraine's maritime border with Romania.
Images also depicted recent damage to buildings on the island, which gained notoriety for the foul-mouthed defiance of its Ukrainian defenders during the initial stages of the invasion.
Russia suffered additional blows on the battlefield as Ukraine expelled its troops from the region surrounding the second largest city of Kharkiv, the quickest progress since the Kremlin's men were removed from Kyiv and the northeastern part of the country over a month ago.
Journalists from Reuters have confirmed Ukraine's control of terrain extending approximately 40 kilometers east of Kharkiv to the banks of the Siverskiy Donets River.
According to regional officials, two persons were killed by shelling in Dergach, close to Kharkiv, and continued missile attacks surrounding Poltava.
Wives and relatives of Ukrainian combatants holed up at the Azovstal steel complex in the southern port of Mariupol marched and called for their rescue in the Ukrainian capital, Kyiv. Russian forces have started bombarding the steelworks, the final stronghold of Ukrainian defenders in a city that has been under siege for more than two months and is now almost entirely under Russian control.
Maria Zimareva, whose brother is inside the steelworks, stated, "I want all the defenders who are there to return home to live a normal life with their children and relatives" "They deserve it. Why are they unable to roam the streets with their loved ones while others can? Why does no one aid them?"
Kyiv stated that it was striving to rescue the severely injured personnel.
"We have begun a new round of negotiations regarding the (evacuation) operation's road map. And we will begin with the severely injured "Vice-Premier Iryna Vereshchuk stated on 1+1 television.
As fighting persisted across the country, diplomatic pressure on Russian President Vladimir Putin increased.
The Thursday announcement of Finland's intent to seek NATO membership, and the anticipation that Sweden will follow suit, would result in the growth of the Western military alliance that Putin sought to avoid.
Abandoning the neutrality, they maintained throughout the Cold War would be one of the most significant developments in European security over the past several decades.
Moscow described Finland's declaration as hostile and warned of unspecified "military-technical" reprisal.
The foreign ministry stated, "Helsinki must be aware of the responsibility and consequences of such a move,"
Secretary-General of NATO Jens Stoltenberg stated that the Finns would be "warmly welcomed" and pledged a "smooth and swift" admission procedure.
The White House supported this action.
"We would support a NATO application by Finland and-or Sweden should they apply," stated press secretary Jen Psaki.
Finland's 1300 km border will more than treble the length of the US-led alliance's border with Russia, putting NATO guards within a few hours' drive of the northern fringes of St. Petersburg.
Putin mentioned NATO's possible expansion as one of the primary motivations for his February beginning of a "special military operation" in Ukraine.
Thursday also witnessed the escalation of conflicts over Russian energy exports to Europe, which remain Moscow's primary source of finances and Europe's primary source of heat and electricity.
Moscow warned it would block gas deliveries to Germany via the major pipeline over Poland. At the same time, Kyiv said it would not reopen a pipeline route it closed this week unless it regained control of pro-Russian fighter-held territory. The price of gasoline in Europe increased.